The Asus ML249 has a maximum contrast ratio of 50000000:1. That's over two times the contrast ratio of a 20000000:1 PC monitor, which is the most frequently found contrast ratio. Across all PC screens that were released around the same time as the ML249 the worst contrast ratio is Mega Contrast and the best is 100000000:1.
We think you might also be interested in some of the other flatpanel monitors that have a 50000000:1 dynamic contrast ratio currently available including because of it's better review score, the PB238 (£140.00), or the VE278 both from Asus or the AOC I2473 (£99.59).
If you want a flatpanel monitor with a higher contrast ratio then you might want to consider the PB238Q (80000000:1), the VG248QE (£185.99) (80000000:1), or the MX239H (£166.37) (80000000:1) all from Asus which is also higher rated.